The invention relates to an air spring for air spring axles with a cover connected to the vehicle frame and a piston connected to the rearward end of a pull rod of the axle arrangement as well as a roll bellows connected between the cover and the piston.
An air spring of the aforementioned kind is known for example, from German Patent 31 47 231. For attaching to the rearward end of a pull rod, the known piston is closed off at the lower end by a bottom plate which is connected to the pull rod by screwing and, on the other hand, is connected by screws to the piston. Such air springs in practice have proven successful, however, the massively constructed bottom plate as well as the piston must be embodied with precise guide surfaces in order to ensure in the mounted state a moisture and dirt-tight connection between the piston and the bottom plate. It is also disadvantageous that the bottom plate must have a minimum thickness in order to provide sufficient stability and stiffness of the bottom plate in the area of force transmission about the connecting points and contact surfaces with the pull rod and to thus provide sufficient stability to the piston. This means that a relatively large mass is arranged in the area of the unsprung mass of the axle arrangement. Furthermore, even minimal leaks at the connection between the piston and the bottom plate can result in moisture entering the interior of the piston and in increased corrosional stress.
For avoiding such an increased corrosional stress, additional corrosion protective measures or the use of more expensive corrosion-resistant materials is required.
It is therefore an object of the present invention to provide an air spring for air spring axle arrangements of the aforementioned kind such that they are of a simple design, can be manufactured inexpensively, and overcome the aforementioned disadvantages.